[HELP] best practice of preparing tempered hardboard for oil painting

​Dear MITRA conservators,

appreciate your advice on the best practice of how to preparing an engineered wood support, like tempered hardboard, for oil painting. 

First, do we need to apply SIZE first? some peopel strongly direct wood must be size and sealed before apply acrylic gesso ground. the reason is if apply acrylic gesso directly on wood, its water content will wrap the panel, while if sized with a layer, then the water from gesso layers will not distort the panel. 

however, i had a doubt that the acrylic product used as size still had water content and all acrylic is porous, then how would it prevent wrapping since itself contains water and how it “seal” since it is porous? 

i am not quite sure how much different chemically the acrylic “size” medium different as acrylic gesso, as they should both be similar acrylic resin, then why cannot acrylic gesso be used as size, primer, ground all in one?

2nd, how to remove residue oil on tempered hardboard for optimum acrylic gesso adhesion? i assume the surface reflection is due to residue oil, and i wipe with IPA, but these shinny area still remains. and i brush a layer of water and find it beeds up. so it suggest i didnt sucessfully remove the oil residue. so any better way to do that and method to verify its removal?

3rd, the tempered hardboard surface is very gloss and smooth, so to welcome adhesion i see suggestion of sanding, so can we use scotch brite instead of sand paper? as i am afraid sanding too much. 

thank you.